Re: LTSpice model for a SiC MOSFET

On Mon, 19 May 2025 09:33:28 -0400, legg <legg@nospam.magma.ca> wrote:

>
The drain swing is actually 1.67 times the supply voltage, but it does
need two switching devices and a specially wound transformer (and we
know how reluctant you are to design them or get them made).
>
It is probably going to be too expensive for the application, and we'd
be grateful for your insights into a cheaper alternative. I can't think
of one.

>
I'd keep it simple and repurpose a backwards commodity CCFL ($0.50)
transformer, in a low frequency (20-50KHz) buck regulator 'of sorts'.

A ccfl transformer is ideal for the HV step-down application, and dirt
cheap is a side benefit.

They often have several windings, which helps build oscillators. More
details might involve using a search engine.

>
A 1KV mosfet (why SIC?) would act as it's own TVS if the source was
really self-limited. 2$
>
Trickle charge for start-up, with all control power on the LV side;
an intermediate 8-20V rail.

I'd expect that the tranny and one transistor and a few passives would
make a basic step-down converter without low-side logic to power up.
Parts cost could get below $3 for a regulated 1K to 3.3 supply, $2 in
quantity.

>
From there it's a matter of your techy arranging 'who's on first'
in a sensible manner.
>
RL